Mechanical mechanism of noise reduction performance of rubber granular asphalt mixture under freeze-thaw cycles

To elucidate the meso-mechanical mechanisms governing the evolution of noise-reducing performance of rubberized asphalt mixtures under freeze-thaw cycles, laboratory triaxial compression and uniaxial dynamic modulus tests were conducted to compare the mechanical performance of rubberized and conventional asphalt mixtures under varying freeze-thaw conditions. Based on these results, discrete element models representing different freeze-thaw states were developed using automatic calibration of meso-scale parameters, and their reliability was validated by comparing stress-strain responses from experiments and simulations. The noise-reducing mechanisms of rubberized asphalt mixtures were further interpreted from meso-scale responses, including particle displacement, force chain networks, and energy dissipation. Results indicate that with increasing freeze-thaw cycles, the dynamic modulus, phase angle, and overall structural stiffness of rubberized mixtures gradually decrease, while frictional and damping energy dissipation increase. After 15 cycles, frictional and damping energy dissipation increased by 0.73 J and 0.23 J, respectively, exceeding those of conventional mixtures (0.38 J and 0.13 J). Meso-scale analysis shows that the load-bearing skeleton is primarily composed of coarse and medium aggregates, with rubber particles contributing minimally to force transmission. This study provides a reference framework for meso-mechanical analysis and numerical simulation of asphalt mixtures under freeze-thaw conditions.